NONLINEAR RESTORING FORCES OF AN OFFSHORE PLATFORM

The method of calculation of non-linear restoring forces presented in this paper is simple, concise and feasible to apply easily in the calc ulation of restoring forces of platforms in order to simulate motion r esponses of offshore platforms in the time-domain. In this method, hyd rostatic restoring forces and moments are related to the translational and/or rotational displacements. Calculations of non-linear yaw, roll and pitch restoring moments are based on the catenary type of mooring s. Although the method presented here is a simple one, it is capable o f the calculation of restoring forces for use in the time-domain motio n simulations of offshore platforms, with an acceptable degree of accu racy when the numerical simulation results were compared with the expe rimental measurements. (C) 1997 Elsevier Science Ltd.